in terms of the Northampton outbreak we have of course been here (as in most likely that type of outbreak) before.
South Holland had massive surge in cases in the first half of May. With a weekly peak cases per 100,000 higher than anywhere else in England so far; that may of course change with Northampton. For simplicity I've assumed 300 confirmed cases in Northampton this week; it could of course be higher again, but also it likely that a decent minority of those confirmed at Glencore may live in neighbouring council areas.
South Holland as the graph shows took a few weeks to get under control, but has remained as quite low levels since then. Hopefully a similar grip can be applied in Northampton.
Different environments of course though. Population of 95,000 in South Holland as compared to 224,000 in Northampton; and Northampton would fit into the area of South Holland 9 times over. But this is the sort of outbreak that needs to be managed downward quickly - most of the current watched areas seem to be lingering on for weeks merging into months.